Idiopathic interstitial pneumonias (IIPs) are associated with an increased risk of lung cancer. Glasgow prognostic score (GPS), which uses serum C-reactive protein (CRP) and albumin levels to indicate systemic inflammatory response and nutrition level, has been reported to be a predictor of overall survival in patients with various types of cancer. We evaluated the usefulness of GPS for prediction of survival of patients with both lung cancer and IIPs following a lung resection procedure. Patients with IIPs who underwent lung cancer resection from January 2006 through December 2015 were investigated. Routine laboratory measurements, including serum CRP and albumin for determining GPS, were performed before the operation. Univariate and multivariate analyses with a COX proportional hazards regression model were used to identify independent risk factors for overall survival (OS), relapse-free survival (RFS), cancer-specific survival (CSS), and other disease-specific survival (ODSS). A total of 135 patients underwent lung resection during the study period. Multivariate analysis selected sublobar resection (p = 0.035), UIP pattern (p = 0.025), and GPS of 1-2 (p = 0.042) as predictive factors associated with OS, while GPS of 1-2 (p = 0.039) was shown to be a predictive factor associated with RFS. Multivariate analysis also revealed pTNM (p < 0.001), usual interstitial pneumonia pattern (p = 0.006), and GPS of 2 (p = 0.003) as predictive factors associated with CSS, while univariate analysis indicated pTNM (p = 0.042), GPS of 1 (p = 0.044), and %DLCO (p = 0.038) as predictive factors associated with ODSS. GPS is an independent prognostic factor of OS and RFS in lung cancer patients with IIPs undergoing a lung resection procedure. Furthermore, a GPS of 2 was found to be associated with CSS following lung cancer resection, while a score of 1 was associated with ODSS.